基于小波变换的在役管线漏磁信号的去噪

采用漏磁法对在役管线进行无损检测时,所采集的信号中含有大量的噪声需要去除。文中介绍了小波变换的基本理论及检测信号和噪声信号在小波变换下的特性,说明了去除漏磁信号噪声的原理。在仿真试验中采用二阶双正交样条小波为小波函数,选用软硬阈值折中法和自适应阈值处理小波系数,结果表明将小波变换应用于在役管线漏磁检测中,能很好地去除噪声,提取出有用信号。

The De-noising of MFL Signal from the Working Pipes Using Wavelet Transform

When magnetic flux leakage(MFL)appeared in nondestructive test of working pipes,the MFL signal contains a lot of noise that needs to be reduced.This paper introduces the basic theory of wavelet transform and the characteristic of MFL signal and noise under wavelet transform,the principle of MFL signal de-noising is also illustrated.In a simulation experiment,a second-order spline wavelet is chosen as wavelet function and a compromised algorithm between soft-thresholding and hard-thresholding and adapting threshold value are adopted for processing wavelet coefficients.The result indicates that noise can be eliminated and the useful signal can be extracted using wavelet transform in MFL of working pipes detecting.